Total number of balls = 18.
Number of red balls = x.
(i) Number of balls which are not red = 18 − x
∴ P(getting a ball which is not red) =
=
Thus, the probability of drawing a ball which is not red is .
(ii) Now, total number of balls = 18 + 2 = 20.
Number of red balls now = x + 2.
P(getting a red ball now) =
=
and P(getting a red ball in first case) =
=
Since, it is given that probability of drawing a red ball now will be times the probability of drawing a red ball in the first case.
Thus,
Thus, the value of x is 8.